The present invention relates to an apparatus for opening film cassettes in general, and more particularly to an apparatus for opening substantially rigid synthetic plastic film cassettes. Still more particularly, the apparatus is particularly suitable for opening synthetic plastic film cassettes of the type having a pay-out section and a take-up section which are connected by a film guiding web section of substantially U-shaped cross-section.
Amateur films of all kinds, be it films used for still pictures or films used for motion pictures, are seldom developed at home any more. They are now almost exclusively developed in larger or smaller photographic laboratories. In such laboratories, economy of operation is of course of considerable importance. Insofar as cassette-type films are concerned, such economy of operation is enhanced by the fact that the larger laboratories usually have apparatuses which automatically remove film from the cassette and wherein the removed films are successively connected to one another, i.e. by adhesive means, so that a long chain of individual film strips is obtained which are then also automatically processed in the processing equipment.
In smaller laboratories the rather complicated and expensive apparatuses for extracting the film from the cassette and for connecting successive films to one another are usually not economically feasible, especially since the individual films are usually separately developed in these smaller laboratories. Such smaller laboratories still require an apparatus for opening the film cassettes so as to permit extracting of the film, but such an apparatus should be very much simpler, less complicated and less expensive than the automatic equipment used on the larger laboratories. Even in the larger laboratories, however, such a simple and less complicated type of apparatus is desirable, as long as it is capable of opening up the film cassette even if the trailing leader of the film has been pulled out of the pay-out section and into the take-up section, since the automatic equipment for extracting the film will operate only if some of the film or at least the trailing leader on the film still extends out of the take-up section and is therefore accessable, usually on the U-shaped web section which connects the take-up section and the pay-out section of a film cassette.
The prior art has proposed an arrangement for cracking or breaking open a film cassette, wherein a chisel-like member is utilized which is made to penetrate through a seam of the cassette, i.e. a seam at which two parts of the synthetic-plastic cassette have been bonded together, and which member is tilted normal to the plane of the seam after penetrating into the seam so as to lever the two parts of the cassette apart and permit access to the film.
Another prior-art proposal suggests using a chisel-like member having a width corresponding substantially to the width of the film. This member is inserted into the slot which is formed in synthetic-plastic film cassettes between the take-up section and the web section, and the member is then tilted so that its tip which has been inserted through the slot travels in an arcuate path and levers off the web section and a part of the take-up section in order to permit access to the film in the interior of the latter.
The prior-art proposals suffer, however, from the disadvantage that damage to the film by the chisel-like member can never be reliably precluded. At the very least the exposed film end may be bent, scratched or torn, so that further handling becomes difficult, for example securing of the film end to a preceding or succeeding film strip. Also, this levering-off requires the exertion of a relatively significant force so that the apparatuses according to the prior art must be constructed in a relatively complicated and/or expensive manner.
However, these are not the only disadvantages of this prior-art equipment. It has been found that there is danger of injury to the hands of an operator, as the operations must be carried out in a dark room so that the apparatus cannot be visually observed. Also, a special clamping device must be utilized in each prior-art apparatus of this type for holding the cassette while it is being opened. This requires an additional operation on the part of the operator and of course further complicates and makes more expensive the overall construction of the apparatus.